Method of plasma etching high-K dielectric materials with high selectivity to underlying layers

Abstract

A method of plasma etching a layer of dielectric material having a dielectric constant that is greater than four (4). The method includes exposing the dielectric material layer to a plasma comprising a hydrocarbon gas and a halogen containing gas.

1. A method of plasma etching a layer of dielectric material, comprising:
 etching said dielectric material layer in a plasma comprising a hydrocarbon gas and a chlorine containing gas, wherein the dielectric material is at least one of HfO 2 , HfSiO 2 , ZrO 2 , Al 2 O 3 , ZrSiO 2 , and TaO 2 , wherein the hydrocarbon gas is a gas selected from the hydrocarbon gas group consisting of methane, ethylene, propane, and butane, and wherein said chlorine containing gas is Cl 2 . 
 
   
   
     2. A method of plasma etching a layer of dielectric material, comprising:
 etching said dielectric material layer in a plasma comprising a hydrocarbon gas and a halogen containing gas, wherein the dielectric material is at least one of HfO 2 , HfSiO 2 , ZrO 2 , Al 2 O 3 , ZrSiO 2 , and TaO 2 , wherein the hydrocarbon gas is a gas selected from the hydrocarbon gas group consisting of methane, ethylene, propane, and butane, and wherein said etching step further comprises providing a gas flow ratio of Cl 2  to CH 4  in the range of about (0.025:1) to (150:1). 
 
   
   
     3. The method of  claim 2  wherein said etching step further comprises:
 providing a gas flow ratio of Cl 2  to CH 4  in the range of about 4:1. 
 
   
   
     4. The method of  claim 2  wherein said etching step further comprises the step of:
 supplying 5 to 300 sccm of Cl 2  and 2 to 200 scan of CH 4 . 
 
   
   
     5. A method of plasma etching a layer of dielectric material, comprising;
 etching said dielectric material layer in a plasma comprising a hydrocarbon gas and a halogen containing gas, wherein the dielectric material is at least one of HfO 2 , HfSiO 2 , ZrO 2 , Al 2 O 3 , ZrSiO 2 , and TaO 2 , wherein the plasma further comprises a reducing gas. 
 
   
   
     6. The method of  claim 5  wherein the reducing gas comprises carbon monoxide (CO). 
   
   
     7. The method of  claim 2  wherein said etching step further comprises the step of:
 supplying 5 to 300 sccm of Cl 2 , 2 to 200 sccm of CH 4 , and 5 to 300 sccm of CO. 
 
   
   
     8. The method of  claim 2  wherein said etching step further comprises:
 providing a gas flow ratio of Cl 2  to CH 4  in a range of about (0.025:1) to (150:1), a flow ratio of Cl 2  to CO in a range of about (0.016:1) to (150:1), and a flow ratio of CO to CH 4  in a range of about (0.025:1) to (150:1). 
 
   
   
     9. The method of  claim 2  wherein said etching step further comprises:
 providing a gas flow ratio of Cl 2  to CH 4  to CO of about (1.0):(0.5):(1.0). 
 
   
   
     10. The method of  claim 2  further comprising the step of:
 applying a bias power to a biasing element of up to 100 W. 
 
   
   
     11. The method of  claim 2  further comprising the step of:
 applying an inductive source power to an inductively coupled antenna of 200 to 2500 W. 
 
   
   
     12. A method of plasma etching a layer of dielectric material, comprising:
 etching a workpiece having a dielectric material layer comprising hafnium-dioxide (HfO 2 ) in a plasma comprising a hydrocarbon gas and a halogen containing gas; and 
 maintaining the workpiece comprising the dielectric material layer of hafnium-dioxide (HfO 2 ) at a temperature between 10 to 500 degrees Celsius. 
 
   
   
     13. A method of plasma etching a layer of dielectric material, comprising:
 etching said dielectric material layer in a plasma comprising a hydrocarbon gas and a halogen containing gas, wherein the dielectric material comprises hafnium dioxide (HfO 2 ), and wherein the hydrocarbon gas is a gas selected from the hydrocarbon gas group consisting of methane, ethylene, propane, and butane; and 
 maintaining a workpiece comprising the dielectric material layer of hafnium-dioxide (HfO 2 ) at a temperature of 350 degrees Celsius. 
 
   
   
     14. A method of plasma etching a layer of dielectric material, comprising:
 etching a workpiece having a dielectric material layer comprising hafnium-silicate (HfSiO 2 ) in a plasma comprising a hydrocarbon gas and a halogen containing gas; and 
 maintaining the workpiece comprising the dielectric material layer of hafnium-silicate (HfSiO 2 ) at a temperature between 10 to 500 degrees Celsius. 
 
   
   
     15. A method of plasma etching a layer of dielectric material, comprising:
 etching said dielectric material layer in a plasma comprising a hydrocarbon gas and a halogen containing gas, wherein the dielectric material comprises hafnium-silicate (HfSiO 2 ), and wherein the hydrocarbon gas is a gas selected from the hydrocarbon gas group consisting of methane, ethylene, propane, and butane; and 
 maintaining a workpiece comprising the dielectric material layer of hafnium-silicate (HfSiO 2 ) at a temperature of 350 degrees Celsius. 
 
   
   
     16. A method for plasma etching a workpiece having a layer of hafnium-dioxide comprising the steps of:
 supplying chlorine gas and methane gas at a flow ratio in a range of about (0.025:1) to (150:1); 
 maintaining a gas pressure of between 2–100 mTorr; 
 applying a bias power to a cathode electrode of between 5 to 100 W; 
 applying power to an inductively coupled antenna of between 200 to 2500 W to produce a plasma containing said chlorine gas and said methane gas that etches the workpiece; and 
 maintaining said workpiece at a temperature between 10 and 500 degrees Celsius. 
 
   
   
     17. A method for plasma etching a workpiece having a layer of hafnium-silicate comprising the steps of:
 supplying chlorine gas and methane gas at a flow ratio in a range of about (0.025:1) to (150:1); 
 maintaining a gas pressure of between 2–100 mTorr; 
 applying a bias power to a cathode electrode of between 5 to 100 W; 
 applying power to an inductively coupled antenna of between 200 to 2500 W to produce a plasma containing said chlorine gas and said methane gas that etches the workpiece; and 
 maintaining said workplace at a temperature between 10 and 500 degrees Celsius. 
 
   
   
     18. A method of plasma etching a layer of dielectric material, comprising:
 etching said dielectric material layer in a plasma comprising a hydrocarbon gas and a halogen containing gas, wherein the dielectric material is at least one of HfO 2 , HfSiO 2 , ZrO 2 , Al 2 O 3 , ZrSiO 2 , and TaO 2 , wherein the hydrocarbon gas is a gas selected from the hydrocarbon gas group consisting of methane, ethylene, propane, and butane, and wherein the plasma further comprises a reducing gas. 
 
   
   
     19. The method of  claim 18  wherein the reducing gas comprises carbon monoxide (CO). 
   
   
     20. The method of  claim 5 , wherein the halogen containing gas comprises a chlorine containing gas. 
   
   
     21. The method of  claim 20  wherein said chlorine containing gas is Cl 2 . 
   
   
     22. The method of  claim 5 , wherein the hydrocarbon gas is methane (CH 4 ). 
   
   
     23. The method of  claim 5  further comprising:
 applying a bias power to a biasing element of 0 to 100 W. 
 
   
   
     24. The method of  claim 12 , wherein the halogen containing gas comprises a chlorine containing gas. 
   
   
     25. The method of  claim 24  wherein said chlorine containing gas is Cl 2 . 
   
   
     26. The method of  claim 12 , wherein the hydrocarbon gas is methane (CH 4 ). 
   
   
     27. The method of  claim 12  further comprising:
 applying a bias power to a biasing element of 0 to 100 W. 
 
   
   
     28. The method of  claim 14 , wherein the halogen containing gas comprises a chlorine containing gas. 
   
   
     29. The method of  claim 28  wherein said chlorine containing gas is Cl 2 . 
   
   
     30. The method of  claim 14 , wherein the hydrocarbon gas is methane (CH 4 ). 
   
   
     31. The method of  claim 14  further comprising:
 applying a bias power to a biasing element of 0 to 100 W.